import { cookies } from 'next/headers';
import { mainPrisma } from './db';
import bcrypt from 'bcryptjs';
import jwt from 'jsonwebtoken';

// JWT 密钥 - 必须通过环境变量配置，不再提供默认值
const JWT_SECRET = (() => {
  const secret = process.env.JWT_SECRET;
  if (!secret) {
    console.error('[SECURITY] JWT_SECRET 环境变量未设置，管理员认证功能将不可用');
  } else if (secret.length < 32) {
    console.error('[SECURITY] JWT_SECRET 长度不足 32 字节，建议使用更长的密钥');
  }
  return secret || '';
})();

const TOKEN_EXPIRY = '24h';

export interface AdminSession {
  id: string;
  username: string;
}

/**
 * 验证管理员登录
 */
export async function verifyAdmin(
  username: string,
  password: string
): Promise<{ success: boolean; token?: string; error?: string }> {
  try {
    const admin = await mainPrisma.admin.findUnique({
      where: { username },
    });

    if (!admin) {
      return { success: false, error: '用户名或密码错误' };
    }

    const isValid = await bcrypt.compare(password, admin.passwordHash);
    if (!isValid) {
      return { success: false, error: '用户名或密码错误' };
    }

    const token = jwt.sign(
      { id: admin.id, username: admin.username },
      JWT_SECRET,
      { expiresIn: TOKEN_EXPIRY }
    );

    return { success: true, token };
  } catch (error) {
    console.error('验证失败:', error);
    return { success: false, error: '服务器错误' };
  }
}

/**
 * 验证 JWT token
 */
export function verifyToken(token: string): AdminSession | null {
  try {
    const decoded = jwt.verify(token, JWT_SECRET) as AdminSession;
    return decoded;
  } catch {
    return null;
  }
}

/**
 * 从请求中获取当前管理员会话
 */
export async function getAdminSession(): Promise<AdminSession | null> {
  const cookieStore = await cookies();
  const token = cookieStore.get('admin_token')?.value;

  if (!token) {
    return null;
  }

  return verifyToken(token);
}

/**
 * 创建管理员账号（用于初始化）
 */
export async function createAdmin(
  username: string,
  password: string
): Promise<{ success: boolean; error?: string }> {
  try {
    const existing = await mainPrisma.admin.findUnique({
      where: { username },
    });

    if (existing) {
      return { success: false, error: '用户名已存在' };
    }

    const passwordHash = await bcrypt.hash(password, 10);

    await mainPrisma.admin.create({
      data: {
        username,
        passwordHash,
      },
    });

    return { success: true };
  } catch (error) {
    console.error('创建管理员失败:', error);
    return { success: false, error: '服务器错误' };
  }
}

/**
 * 生成许可证密钥
 */
export function generateLicenseKey(): string {
  const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
  const segments: string[] = [];

  for (let i = 0; i < 4; i++) {
    let segment = '';
    for (let j = 0; j < 4; j++) {
      segment += chars.charAt(Math.floor(Math.random() * chars.length));
    }
    segments.push(segment);
  }

  return segments.join('-');
}